Improvement in mills



z sheets she et 1.

I.A.HEDGE.S.

MILL.

No. 170,367. M d Nov- 23, 1875.

nrrn STA PATENT OFF- ron.

IsAAc A. HEDGES, OF sr. LoUIs," MISSOURI.

IMPROVEMENT IN MILLS.

Specification forming part of Letters Patent No. 170,367, dated November23, 1875; application filed I June 9, 1873.

To all whom it may concern:

Be it known that I, ISAAC A. HEDGES, of St. Louis, in the county of St.Louis and State of Missouri, have invented an Improved Mill for GrindingCorn, of which the following is a to regularly incline more and morefrom the vertical to the horizontal, as they extenddownward, theteeth-edges on the cone curving backward as they extend downward, and

those on the concave curving in an opposite direction, thus acting toforce the meal downward with increasing speed as it becomes finer, andwould otherwise tend to clog in the? posite direction, so as to tend toforce the grooves between the teeth.

The second part of my improvement consists'in the annular concavebearing that is given to the cone, the cone being supported by its neck,as more particularly described hereinafter, so as to avoid the necessityof the ordinary bridge-tree and step bearing.

In the accompanying drawings, Figure 1 is a top View of the mill, withthe sweep or draft- ]ever removed. Fig. 2 is an axial section. Fig. 3 isa side elevation of the cone. Fig. at is a horizontal section of aportion of the concave, showing the teeth in transverse section. Fig. 5is an axial section of the concave with the cone and other partsremoved. Fig. 6 is a side elevation of the mill with sweep removed.

The outer case or concave consists of a lower portion, A, and an upperportion, B,

its rim 6 The rim c has lugs F for the attachment of the horse lever orsweep by which the mill is driven. The cone or runner con- 'sists of alower portion, G, and an upper por-' tion, H, connected together by ahorizontal joint secured by lugs and bolts 9 g. From the apex of theupper portion H extends the neck or spindle I, which has side bearing inthe head D. The upper end of the neck I is firmly secured in thedriver-frame E, so that the cone is supported by the annular bearing dc.(Before described.) The form and arrangement of the-teeth K upon thecone, and L of the concave are alike. The teeth consist of cutting-edgesextending from top to bottom of the grinding-surfaces. At the top ofsaid surfaces the teeth, both. upon the cone and concave, are vertical,and thus the teeth of that part of the concave are parallel with thoseof the concave at the upper end; but as the teeth extend downward theycurve toward,

-the horizontal, those upon the cone curving backward, (in relation tothe direction of rotation,) and those upon the concave in an opmealdownward with accelerated speed as it passes between the lower portionof the grinding-surfaces, where the sheet of meal is thinner, and where,without this provision, it is apt to choke and check the passage of themeal above it.

It will be understood that the curve of the teeth is not equivalent to aspiral curve, for, in this case, the tendency to force the meal forwardthrough the mill is equal at all points, and as the stratum of meal isthicker at the upper portion of the grindingsurfaces, a larger amounttends to pass than can pass through. the lower portion, Where thesurfaces are set closer, the teeth are smaller and more numerous, andthe meal-space consequently lessened.

The backs 7a of the teeth K and L are concave in transverse section, soas to make the cutting-edge more acute, and to make the corner of thegroove between the teeth more open, to prevent the lodging of meal inthe groove and consequent choking of the mill.

The annular groove at, being closed at bottom, prevents the escape ofoil, and the bearing-ring and groove being both rounded, the I proachmore and more nearly to the horizontal as they descend, substantially asand for the purpose set forth.

2. The concave having teeth L, vertical at their upper ends and curvingin lines so as to approach more and more nearly to the horizontal asthey descend, substantially as and for the purpose set forth.

3. The supporting-head D, of the runner or cone, having annularconcave-bearing d, in combination with driving frame E, having convexrib e, substantially as and forthe purpose set forth.

ISAAC A. HEDGES. Witnesses:

Gr. 0. KALB, E. A. MANNY.

